1. Field of the Invention
The present invention relates to a curved reflector for use in projecting a luminous line on an object by a laser beam and more particularly to a variably curved reflector the use of which enables the spatial configuration of the luminous line to be selectively altered and which is of simple construction.
2. Description of the Prior Art
U.S. Pat. No. 4,693,567, entitled Apparatus for Projecting Luminous Lines on an Object by a Laser Beam, issued to Yasuto Ozakii on Sept. 15, 1987, teaches an apparatus which projects luminous lines on an object by use of a laser beam and which includes a laser system, a lens assembly and a curved reflector. The laser system produces a laser beam. The lens assembly is located at a position subsequent to the laser system and expands the laser beam. The lens assembly includes a concave lens and a convex lens. The concave lens diverges the laser beam. The convex lens is positioned subsequent to the concave lens. The convex lens converges the laser beam to be of a maximum desired width. The curved reflector has a central plane and is located at a position subsequent to the convex lens with the optical axis of the laser beam which extends in the central plane. The curved reflector has a pair of curved side reflecting surfaces which interect along an edge of the reflector. The edge lies in the central plane. The reflecting surfaces diverge symmetrically from opposite sides of the central plane in directions away from the convex lens. The pair of reflecting surfaces thereby reflect the laser beam at different angles with respect to the central plane at respective different positions along the pair of reflecting surfaces and reflect a pair of sector-shaped luminous lines on an object. The sector-shaped luminous lines expand symmetrically from the side reflecting surfaces. The curved reflector has a curved top reflecting surface which extends transverse to and intersects the pair of side reflecting surfaces which extend perpendicular to the central plane. The central plane symmetrically bisects the top curved reflecting surface. The top reflecting surface reflects at different angles at a respective different portions along the top curved reflecting surface and reflect further sector-shaped luminous lines on the object. The luminous lines expand symmetrically from the curved top reflecting surface in directions perpendicular to the pair of sector-shaped luminous lines.
U.S. Pat. No. 3,826,576, entitled Laser Measuring or Monitoring System, issued to Eugene E. Stewart on July 30, 1974, teaches a laser measuring or monitoring system in which a reference plane is established by passing a laser beam through a lens assembly in order to create a focusable diverging planar beam of light. The reference beam is projected tangent to a cylindrical surface of an object with the beam being focused at a point closely adjacent but forward of the surface and projected onto a screen rearwardly of the object. The position of the beam is precisely controlled and any deviation in the diameter of the object is indicated as an interruption of the beam on the screen. U.S. Pat. No. 4,433,780 also teaches system for directing the light into a beam of substantially uniform rectangular cross-section.